1. Field of the Invention
The present invention relates to a process for the hydrogenation of organopolymeric peroxides wherein the nickel catalyst is reactivated. More particularly, it relates to a process for the reactivation of a nickel catalyst which can contain another metal such as copper, chromium, rhenium, iron, or the like and which is used in the hydrogenation of polymeric peroxides.
2. Description of the Prior Art
Heretofore, methods of reactivating nickel catalysts have included such techniques as treating the catalyst with an organic acid or a base and oxidizing the catalyst with oxygen or air and then hydrogenating the same. However, these conventional methods can be applied only on those nickel catalysts which are used for certain reactions. For many reactions, the reactivation techniques are not practical. Certainly, it has not been known to reactivate nickel catalysts which have been used in the hydrogenation of organopolymeric peroxides.
Various diols can be produced by the hydrogenation of organopolymeric peroxides with nickel catalysts such as Raney nickel and nickel which is durable to sulfur. (Japanese Unexamined Patent Publication Nos. 19511/1973 and 43908/1974). These catalysts are substantially poisoned during the hydrogenation of organopolymeric peroxides. Accordingly, the amount of the organopolymeric peroxide which is hydrogenated is limited and depends upon the amount of the catalyst used.
In order to increase the yield of diol per unit amount of the catalyst, the catalyst must be reactivated by a special treatment. One proposed method of reactivating poisoned Raney nickel catalysts has been to heat the catalyst in an alkaline aqueous solution (Japanese unexamimed Patent Publication Nos. 66000/1974 and 88290/1974). However, the method requires different solvents for the hydrogenation of the organopolymeric peroxide and the reactivation of the catalyst. This means an operation must be provided for the replacement of solvent which is a complicated industrial operation.
A need, therefore, continues to exist for a method of reactivating nickel catalysts used in the hydrogenation of organopolymeric peroxides.